Mixed technology MEMS/SiGe BiCMOS digitalized analog front end with direct RF sampling

Abstract

A digitizing analog front end (DAFE) using mixed technology on a single substrate is described. SiGe BiCMOS technology is implemented for the semiconductor components, which include a low noise amplifier and an analog-to-digital converter. Micro Electro Mechanical System (MEMS) switches are used to change the filtering characteristics of several filters, including an anti-aliasing filter and a pre-select and anti-jamming filter.

Description

FIELD OF THE INVENTION[0001]The present invention relates to protection of analog to digital converters (ADC), to the reduction of power consumption and to the maintenance of high signal quality in a radio receiver's analog front end in the presence of large interfering and jamming signals. More particularly, the invention relates to a single chip receiver utilizing micro electromechanical system (MEMS) technology to receive wideband or spread-spectrum signals in a jamming environment with a low resolution ADC, such as in a Global Positioning System (GPS) receiver.BACKGROUND OF THE INVENTION[0002]This invention is applicable to all communication systems. A spread-spectrum system will be used to illustrate its use and effectiveness. Spread-spectrum communication systems transmit information digitally on a carrier that has been modulated with a high-rate pseudorandom binary sequence. The spectrum of the resulting signal occupies a large bandwidth and appears noise-like. The signal is ...

AI Technical Summary

Benefits of technology

[0007]In the light of the foregoing, the invention relates to an integrated circuit digitizing analog front end for a receiver, which includes a substrate; a low noise amplifier (LNA) on the substrate; an analog-to-digital converter (ADC) on the substrate; a plurality of micro electro mechanical system (M

Problems solved by technology

The spectrum of the resulting signal occupies a large bandwidth and appears noise-like.

The signal is subject to intentional or unintentional jamming.

Thus, it is the in band signals that present the greater obstacle to accurate reception of the transmitted signal.

Another effect on system design and system performance in a jamming environment is in power consumption and signal distortion.

In a jamming environment when the jamming signals are not removed near the antenna, the components in the analog front end must be designed with high linearity at the cost of significantly higher power consumption.

Also, the presence of large signals puts greater demands on the phase noise requirements of the system.

Semiconductor switching, due to the semiconductor's limited isolation characteristics, may allow parasitic capacitances from non-selected filters and / or components to effect the performance of a selected filter, resulting in distortion of the filtered signal.

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